Yon of Lesser Ireland

Iom, Yons d'Ierlande la Menor, Yons d'Yrlande

Yon appears to have been a subking in Gaul, captured by Bagdemagus during Arthur's war against Claudas. Bagdemagus added Yon's contingent to his own, and Yon himself seems not only to have gone over to Arthur's side, but to have distinguished himself as one of the best leaders on that side.

King Yon later turns up in Arthur's court, among the barons. After Lancelot was discovered with Guenevere, when Arthur commanded his barons so sentence the Queen without delay, Yon reminded him that it was not the custom to pass any judgments after the hour of Nonne (about mid-afternoon).

Yon was killed in the last battle with Mordred's forces.

Might Yon conceivably be identified with Yonec, the title character in one of the works of Marie de France?